Method of pasteurizing liquids



Aug. 13, 1929. L N 1,724,291-

METHOD OF PASTEURIZING LIQUIDS Filed July 14, 1925 Patented Aug. 13, 1929.

UNITED STATES PATENT OFFICE.

FREDEBIK LASSEN, OF COPENHAGEN DENMARK, ASSIGNOR TO AKTIESELSKABET DE FOBENEDE DRYGGERIER, COPENHAGEN, DENMARK.

METHOD OF PASTEURIZING LIQUIDS.

Application filed July 14, 1925, Serial No. 43,656, and in Great Brltai n June 23,. 1925.

This invention relates to method of pasteurizing liquids. More specifically it relates to a method and apparatus for pasteurizing liquids which contain gases which escape on heating and whose presence in the liquids is desirable. Beer is an important member of this class of liquids.

As is well known, beer is pasteurized after it is bottled. It is extremely important that 10 this pasteurization should be complete, es-

peciallyif the beer is to be shipped. I Owing to the considerable expansion of the liquid on heating, the bottles cannot be filled .entirely. The small air space thus left in the bottle prevents the complete pasteurization of the contents. It is extremely difficultto ensure the pasteurization of the gases in theair space. The air space causes the liquid in the bottle to toss during transport, especially during sea transport. This tossing is detrimental to the liquids, especially if they contain absorbed liquids.

This invention eliminates these drawbacks. According to this invention, the

2% liquid to be pasteurized is heated in expand able containers. The containers are completely, or as completely as practicfable, filled with the liquid. The containers and the contained liquid are thenv heated to the pasteurizing temperature. When the pasteurization is completed, the containers are cooled. The heating of the liquids causes them to expand, thus causing an expansion of the container. On cooling the liquids contract.-' Usually the containers are so constructed that the partial vacuum resulting from the contraction of the liquids, is

insutficient to cause the restoration of the portant consideration is that containers full of liquid are better able to withstand mechanical forces than containers only partially filled. In the process of this invention, the containers after coolingare exposed to an exof the container.

7 aluminium.

ternal pressure suflicient to restore them to their original volume. then completely filled with liquid and the liquid contains the same gases as before pasteurization. According -to this invention the pasteurization process is carried out in containers having an expandable portion.'

This is obtained by constructing the container so that a wall portion shall be made of a thinner or softer metal than the rest I This wall portion expands when the liquid is heated. It may be restored to its original thus restoring the container to its original volume.

This invention may be further understood by reference to the accompanying drawings wherein,

Figure 1 is a side elevation of a pasteurizing plant with part of the tank broken away, showing the containers in place and having their smallest volume. I

Figure 2 shows an expandable container having its greatest volume.

Figure 3 is an end elevation of Figure 1.

Figure 4 is a plan top view of Figure 1.

In the modification illustrated in the drawings, the expandable container consists of a metal bottle a, the bottom of which is made of softer or thinner material than the remainder of the bottle. When the pressure in the interior of the container corresponds to that at the ordinary temperature, the bottom 6 of the container is concave. Owing to the relative weakness of the bot- The container is tom, it may bulge (b Fig. 2) when the interior pressure increases during pasteurization.

For example the bottle may be made of aluminium, the bottle proper being made of hard aluminium and the bottom of softer If such bottles be made to hold they can compete economically with common beer bottles. They maybe produced so cheaply that they need not be returned to the breweries or other pasteurizing plant.

As stated before, a more stable product is obtainable than when containers having a small air space is employed.

Many different devices for pasteurizing the liquids in expandable containers and many different devices for exertin an exterior pressure on the containers a ter pasteurization, may be employed. The pres- 25 liters,

V poses. The vat is also provided with communicating compartments in which the containers are placed. A guide rod (1 runs down the center of the vat. The containers are placed in rows on either side of this rod. Each of the containers rests on a standard 0.

The containers are closed bfia cap 9, provided with the necessary pac ng. A lever e is slidably mounted on the rod d and capable of being swung to either side of the tank. On this lever is a block 7 containing a recess which fits over the cap 9.

- WVhen the containers are heated, the expansion of the liquid forces the bottom from concaye to the convex position. After the containers are cooled, the lever is brought over the cap. The force exerted by this lever combined with the reaction of the standard forces the bottom inwards thus restoring the original volume of the containers.

The above description of m invention is not to be taken as limiting ut rather as illustrative of .my invention which,

I claim is:

1. A method for pasteurizing liquids con-,

taining dissolved gases without loss of gas during pasteurization which comprises heating a volume of the liquid in a confined space whereby dissolved gases are partially liberated but kept in the confined space, coolin the liquid and by external, positively applied pressure, re-dissolving the gases therein.

2. A method for pasteurizing liquids containing dissolved gases, said pasteurization being carried out out of contact with air, which comprises heating the liquid in a confined space, said liquid substantially filling said space, cooling the liquid and by external, positively applied pressure, redissolving in the liquid any gases liberated during'the heating.

In testimony whereof I aiiix my signature. FREDERIK LASSEN. 

